The Facts of Sex in Relation to Metabolism. 259 
suppose yolk to be chemically simpler than protoplasm, and 
although the cytoplasm may run down chemically into yolk, 
which would therefore be katastatic, the life-equation of an 
egg-cell is one in which potential energy is accumulated, and 
one which in its state of maturity has a rich store of reserve 
material. The male cell, on the contrary, has a very small 
store of potential energy, and at its maturity is usually highly 
katabolic. 
If we picture an egg-cell incorporating neighbour- cells, as 
is often the case, and suppose that the additional cytoplasmic 
material thus acquired sinks down into the more stable and 
simpler state of yolk, this sinking down may be called kata- 
bolic. Its result, however, is that the egg-cells become rich 
in stores of potential energy. Nor is the process of yolk- 
forming known with much definiteness. It is possible 
enough that in some cases the material derived from the 
blood may be worked up into yolk, which would be a 
process of constructive metabolism. 
When Mr Ryder says that the spermatozoon “ consists 
mainly of plasma in a highly anabolic condition as chromatin, 
and therefore represents a higher product of constructive 
metabolism than the female,” he is at once illogical and 
incautious. The chromatin of the sperm must be compared 
with the chromatin of the ovum, and not with its yolk; we 
do not know how the chromatin is related to the general 
protoplasmic metabolism, nor do we know that the chromatin 
of a male cell is chemically the same as that of a female cell. 
When, however, we see a small cell manifesting great 
activity for a short period, and unable to replace its loss 
by nutrition, we say that in the life-equation of such a 
= is much less than the ratio a a 
mature ovum. We should not call the sperm an anabolic 
cell, as Mr Ryder does. 
Even Mr Ryder admits that the spermatozoon “has a 
greater capacity for katabolic change than the female, as 
measured by the relative volume of its nucleoplasm, but 
absolutely it has far less, because of its small size, as 
compared with the whole ovum.” But, as we have already 
cell the ratio 
